Cephalad displacement of the internal jugular vein with exposed superior jugular bulb in the middle ear cavity is an anatomical variation that may have a segmental bluish discoloration through the tympanic membrane. This abnormality may be associated with a conductive or sensorineural hearing loss.
Three cases with bluish-appearing retrotympanic masses were recently explored, and an aberrant jugular bulb was found to be the cause in each case. The audiogram in each case was different. Two of the patients were dwarfs with similar forms of chondrodystrophy— achondroplasia and hypochondroplasia. In achondroplasia, secondary irregular ossification of membranous bone at the base of the skull occurs and may lead to a greater risk of vascular anomalies in the middle ear cavity.
West JM, Bandy BC, Jafek BW. Aberrant Jugular Bulb in the Middle Ear Cavity. Arch Otolaryngol. 1974;100(5):370–372. doi:10.1001/archotol.1974.00780040382010
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